Theory of Surface Waves Coupled to Surface Carriers

Abstract

A new type of surface mode of the electromagnetic wave is predicted in the case when charge carriers are located at the boundary of dielectric media. The dispersion relation of the mode is derived and its characteristic feature is discussed. Effect of the surface carrier is represented in terms of characteristic frequency \(\varOmega_{s}\) (=4π N s e 2 / m * c ; N s is density of the surface carrier). The dispersion takes the linear form in the low frequency region (\(\omega{\ll}\varOmega_{s}\)), while it has the square root form (\(\omega{\propto}\sqrt{k}\)) in the high frequency limit (\(\omega{\gg}\varOmega_{s}\)). In contrast to the case to the absence of surface carriers the present mode exists in the frequency region where at least one of the dielectric functions of the adjacent media takes positive value. As a numerical example the dispersion relation is calculated and illustrated for clean surface of p -type InAs.